Problem: Ashley is 3 times as old as Michael and is also 4 years older than Michael. How old is Ashley?
Answer: We can use the given information to write down two equations that describe the ages of Ashley and Michael. Let Ashley's current age be $a$ and Michael's current age be $m$ $a = 3m$ $a = m + 4$ Now we have two independent equations, and we can solve for our two unknowns. One way to solve for $a$ is to solve the second equation for $m$ and substitute that value into the first equation. Solving our second equation for $m$ , we get: $m = a - 4$ . Substituting this into our first equation, we get the equation: $a = 3$ $(a - 4)$ which combines the information about $a$ from both of our original equations. Simplifying the right side of this equation, we get: $a = 3a - 12$ Solving for $a$ , we get: $2 a = 12$ $a = 6$.